Actuating device



Jan. 29, 1952 R. E. SEARS ACTUATING DEVICE 5 Sheets-Sheet l Filed Dec. 21, 1948 INVENTOR. lac/MR0 E. Jam/es 4 7' TOR/VEY Jan. 29, 1952 R. E. SEARS 2,583,800

ACTUATING DEVICE Filed Dec. 21, 1948 I5 Sheets-Sheet 2 INVENTOR.

lP/CHARD 5. 65/1/25 BY ATTORNEY Jan. 29, 1952 R. E. SEARS ACTUATING DEVICE 3 Sheets-Sheet 3 Filed Dec. 21, 1948 INVENTOR. FP/cH/ RD Z. 1554/?5 A TTOR/VE) J T mg Patented Jan. 29, 1952 ACTUATING DEVICE Richard E. Sears, Cleveland Heights, Ohio, as-

signor to Jack & Heintz Precision Industries, Inc., Cleveland, Ohio, a corporation of Delaware Application December 21, 1948, Serial No. 66,563

4 Claims. (Cl. 192-.09)

This invention relates to actuating devices for raising and loweringa load and one of its primary objects is to provide an electrically driven:

load raising and lowering actuator that operates ineither direction at a predetermined speed regardless of the influence of weight being raised or lowered.

Another object is to provide an improved actuator to include, for load raising purposes, a reversible electric motor and driving shaft, an actuator output shaft for driving the load and a drive between the motor shaft and output shaft comprising a planetary reduction gear train driven by the gear train, a torque release mechanism selectively energized by a solenoid for driving an overriding clutch in one direction only for driving the output shaft.

Another object is to provide an improved actuator to include, for load lowering purposes, a centrifugal braking means, whereby when the load is released to drop of its own weight and the motor reversed and the rate of descent of the load exceeds that of the motor shaft the motor current will drop and tend to reverse, release the solenoid and the torque release and set up torque in the over-riding clutch, whereas the excessive speed makes'effective the braking means between, the torque release carrier and the housing to brake the load speed to normal.

A further object isto apply and adapt such a load raising and lowering actuator to aircraft for extending and retracting landing gear, bomb bay doors and the like where the latter may be of the drop type for extension but under control of the actuator.

With the foregoing and other objects in view the invention resides in the combination of parts and in the details of construction hereinafter set forth in the following specification and appended claims, certain embodiments thereof being illustrated in the accompanying drawings, in which: I

Figure 1 is a viewin longitudinal section of the actuating device, with a fragmentary portion of the motor housing being shown in side elevation;

Figure 2 is a view in side elevation of the actuating device, showing in dotted lines the solenoid, pull rod, gears driven by the output shaft and the driven shaft, representing the work to be driven.

Figure 3 is a detailed enlarged view in longitudinal section of the brake assembly including the drums carried by the housing and the spring and ball operated brake shoes carried by the driving barrel.

Figure 4 is a viewin section taken along line 4-4 of Figure 1 showing the over-riding clutch; Figure 5 is a schematic view showing the drive from the motor and the work, including the motor shaft, reduction gear train, torque release, over-riding clutch, output shaft'and gearing between the latter and. the work;

Figure 6 is a schematic partial view in side elevation of an airplane, showing the actuator and its driving connection with a retractible land ing gear; and I Figure 7 is a wiring diagram of the actuator unit. a I I Referring more particularly to the drawings, Figure 5 is a general schematic diagram of the actuating device, in which an electric motor I drives a shaft 2 carrying a pinion 3 that forms the sun gear of a planetary gear system by meshing with planet gears 4 that mesh with a stationary internal gear 5. The planet gear car-- rier 6 is integral with a pinion I that-meshes with internally toothed clutch plates I6 alternately arranged between externally toothed clutch plates I'l meshing'with the plate carrier B'of a torque" release device, shown in greater detail in Figure 1 and to be later described. The output shaft 9 carries a bevel gear II) for mesh witha bevel gear I I carried by member I2, representing the work to be operated in either direction; For operation of the work in one direction, such as the retraction of an aircraft landing gear, the drive of the output shaft by the carrier 8 is through clutch plate 38 andgear 20 of shaft 9 and through an over-riding clutch I3 to output shaft 9, whereas, in extending the'landing gear by motor drive the drive from carrier 8 to the output shaft is in the opposite direction and by-passes over-riding clutch I3 and is through clutch plate 38 of the torque release device to gear 20 carried by theoutput shaft 9.

Referring to Figure 1, that part of the housing I4 shown broken away and in elevation, houses a reversible electric motor for driving a hollow shaft 2 and a solenoid 3'! for longitudinally extending and retracting a solenoid shaft I5 disposed inside of the hollow motor shaft 2.

The torque release device comprises a series of internally toothed clutch plates I6 that mesh with pinion 1 that is integral with the planet carrier 6. Alternately arranged between clutch plates I6 are a seriesof clutch plates N that are externally toothed to be rigid with member l8 of the plate carrier, or barrel, 8. In addition to this series of plates there are additional plates 19 carried by member I8 of the barrel. Arranged to engage with plates I9 is a plate 38 internally toothed to mesh with gear 20 that is integral with the output shaft 9. Member I8 is adjustable longitudinally and held in adjusted position by nuts 2|. A guide pin 22 and coil spring 23 serves as a means of releasing clutch plate face friction.

When the-motor switch is actuated to turn the motor shaft in the proper direction for landing gear retraction, the solenoid 3'! is energized to;

retract its shaft I5 to the left. This shaft,.ior pull rod I5, carries a rigid enlarged knob 24th'at bears against a ball bearingassembly 215,- forcing. it and a convex spring 26 torthezle'ft .againstither 'thejioyersri'dingaclutch: I 3 ?:to; the output shaft 19.

Intotherrwords, the-pinion .3 of the motor: shaft: 2sme'shing; with. the: planet: gears: 4, rotate the lattenrabout their." pivots 2-1,- as ther'planet' gears 4 mesh with the stationaryinternal. gear. 5.

Thus the i: planet I carrier, 6," which ,1 supports the planet :gearr: pivotsrZI;- is? rotated and: drives its integral: piniorril .1 This; pinionil in; meshing with,

the internally toothed plates I6;=, and: plates I:Ii:'anol=:.=Il of theetorquerelease mechanism being in frictional drive relationship, the torque:

releasexand its carrier;;,or barrel- 8; are driven. Barrel 8-carries an: over-riding: clutch I3;E shown in detail: im-EigureA-and later jtQ be: described: in detail. When 513116? inputushaft 2 andnbarrelt arearotatingt in:the aboveedescribed :d-irection f orlanding v; gear retraction the 1: overaridin clutch I-3:.-:is effectiyer-tovtransmit such rotational drive to thee output; shaft- 9- and -is .1 ineffective as a driyawhen the barrel: 8 ,isirotatedain, the opposite: directions Referrin vto FigureA; theoverrriding clutch,. referred: tlr-generally asz. I kin-Figures: 1 andv 5,; comprises an outeramemberi 28 rigid-with barrel 8; arsseriesrof.spragsxZHoined:togethenbya spring? Silvand San inner; member 31. keyed: toethe outs pntishaft 9;: Asv .indicated:;by the arr,ow, .rota-- tibrr-aof-zthe wbarrel-ztl -and- -outer; member 2 8 1 in, acounterclockwise direction, renders the; over.-

riding-- clutch I 3' an.- eifectiveemeans tto drives the output-shaft 9,1whereas, rotation in-the oppositedirection is not ,transmittedto. the output, shaft.-

rssstated beforaqone of the obiectsof the in. vention is tovemploy, withinnlimits; the weight ofcthe-landing-gear as: an: aiding ,f actor in. extenssloniwvv In otherwords; the landingi gear. isof the. drop, type it being unnecessaryr to-dri-vethe landing gear. into iextensicnaas .gravityv will: ac-

complishrthis: However, I desireto: regulatethe speedvofedrop and also insure extension in theevent that the-force of: gravity failsain completeextension of "the landing-gear;

When it :is desired to extend the'landing gear, it is manually-released fromilockedposition. and. the; motorswitch. I changed itch-reverses the drive OfrthGiIIlOtOr shaft.- The'platess I6-:and. I'Lof the :torque: releaseea-re-e still: compressed by pull rod. I 5. The ..-landing,- gear? is; thus free .--to drop, by gravity: If, however; the; speed. of gravity drop .-of the landing: gear 7 tends. to exceed. the speed: of; the; motor shaft the. motor current drops. and... tends to..r,ev,erse.. direction... In the meanwhile when the motor-currentreduces, to assmallvalue, the solenoid 3llreleases, disengaging the pull rod I5 and destroys the friction be- 4 tween the plates I6 and H of the torque release. This, by itself, would permit the landing gear to drop more rapidly. However, since the overriding clutch I3 is in the same direction, even if the rotation is in the opposite direction, there issopposite :engaging torqueiatthis point;

This excess-speed Will then cause sufficient centrifugal force to be set up to force a series of balls 32, which are rotating at the same speed, tobethrown radially outwardly from their positions shown in dotted lines into their positions sh'owninrfull' linesxin Figure 3. This forces the ballretaining platesx33 and 34 apart against the action ofspring 35' so as to form a friction brake on the stationarymembers 39 and 40 to render thentorque.releaseeifective so as to slow down the speed of drop of the landing gear. As soon as this-drop speed slows down sufficiently, springs 35 will force the balls 32 back into their positionssshowni in:full-linesv and destroy-the .effecti-veness. of theabrakeiassemblyi Inifnrt-hen'deetail, members: 39 and. 40 are; carriedrby, member: 4:I',*which isrigid:withrthe'stationary:housing and; held-:in-place by: a screw-threaded ring144; Ring; 44 receives: bolts-:45 to holdtthe twoiad-joiningz sections of the housing together. The twopbrake; shoesw33 :-and:3 4* have oppositely; concave bevelled facesw to receive a series .of-fcircularl-y arranged balls 32 and n the outer. extensions 2 of. thelshoes receive a series of 1 bolts .36: Bolts: 36;: extend slidably; through. shoe 534 and; is :screw threaded in sho 33. Springs 35,-surrounding; bolts 36, urge the shoes vtogether.:awayvfrombinding fric:

tional engagement with:v brake drum members. 391and- 4e.- Bolts-36 lconnect -the-shoes to barrel 8, which is a rotary driven element, Aswa'further; refinement, .the opposed;-.concave--innerfacesrof the :shoesare so: formed, as-tov have substantially straight. surfaces :46, ,boundedmadially outward-- ly :by ledges 42,; and :sharplya-converging bevelled? surfaces, 43' radially;- outwardlyof. the. ledges-.

At: a :normal unexcessive speed of: rotation ofbarrel 8;,andgconsequently: of zthe {shoes-of thebr-akeeassembly;spring; 35 maintains: the: balls- 32; in; theirtinn'er positionsrshowna-in dottedeli-nesv in: Figure: 3-, and; shown. in. ifull. lines in Figure 1; betweenrithe substantially straightsurfacess lfii Whbny. however-,1 thBESDBBdLZOfiTOtQtiDH".OfTbaI'IBI' a; andnthe 2 brake "shoesi'33 'l' andv 34; becomes excessive, balls 32; in'being ithrowntradially outwardl'yr by centrifugal force; first :ride" over: the: ledgesi- 42 and then suddenly" become increas= ingly effective, dueatonthe sharpi inclines 43"to' quickly and effectively spread shoes 33' an-d 34 toforce them against stationary drums 39'and 48"as a quickly effective brake.

Member IZh'as been previously referredto as'the load,'or'the workto bedone. It'hasalso" been'referredto "as representing-a drop-type'air craft landing gear, a bomb bay door; or" the like. The purpose of Figure 6 is merely to ShOW the actuator secured bysuchmeans asa'bracket 56) to an aircraft that" is schematically shown;

Member I2 is shown to" have-"external screw" threads. 41 that engage internal screwthreads in. a collar 48. Also pivotally connected; to, the aircraft at52 is a landingggearshoclr' .absorbing; strut 53;,of conventional design, that" is pivotally connected atits lower end to, axle. 5] of a landingwheel 54. A cross strut mayhave itsends pivotally connectedtdthe strut 53'and collar 48.. The landingv gearpisofithe drop type.

in that upon release oith'e, usualjlatch to hold,

it retracted within the aircraft, the gravityeffect and ed into the position shown in Figure 6 for landing purposes.

In Figure 7, I have shown a wiring diagram for the actuator. The armature 51 of the actuator motor is shown to be connected at its one end through an interpole winding 60 to the solenoid, here shown by electrical symbol at 6!, and to an electrical source 62 and thence to a double throw switch 63 alternately engageable with spaced contacts 64 and 65. The other end of armature 57 may be connected by a line through a series field winding 59 for clockwise rotation of the armature, to contact 65, and through a series field Winding 58, for counterclockwise rotation of the armature, to contact 64.

In the landing gear extension operation the motor I is producing positive torque in the opposite direction to that required in retraction of the landing gear. This torque is transmitted through the planetary system and through the torque release mechanism which is again effective to drive the barrel 8. However, since the torque is in the opposite direction to that required for landing gear retraction, the overriding clutch [3 will not engage the output shaft 9 because the sprags 29 of the over-riding clutch [3 are positioned for drive in the other direction. Therefore, the torque set up by the rotation of the barrel 8 is transferred through the single clutch plate 38, whose internal teeth mesh with pinion 20 rigid with the output shaft 9, to drive ,the latter, the bevel gear and the work l2.

From the foregoing, it will be seen that there has been provided an effective and foolproof mechanism that is particularly adaptable as a means for the retraction and extension of aircraft landing gear including a manually and automatically reversible electric motor, a reduction gear train, a torque release mechanism rendered effective by a solenoid and pull rod and an over-riding clutch driven one way by the torque release mechanism for landing gear retraction. There has also been provided adequate means for utilizing the weight of the landing gear for drop type extension, brake means for the prevention of excessive drop speed and torque release driving mechanism for insurance of complete extension.

It is to be understood, that while the assembly has been described as particularly adapted for use as a means of retraction and extension of landing gear, it is also adapted for other uses, especially for rotatably driving elements selectively in either direction.

I claim:

i. In a load raising and lowering actuator, a reversible electric motor and shaft, an actuator output shaft adapted to drive the load and driving means between said motor shaft and output shaft including a reduction gear train driven by said motor shaft, a multiple friction plate torque release in engagement with said gear train carrier for said torque release, an over-riding clutch in driving engagement with said torque release carrier and output shaft, a solenoid, a solenoid rod operated by said solenoid to be retracted when said solenoid is energized to compress the plates of said torque release for rendering said torque release an effective driving means between said gear train and said carrier, for raising said load while said motor and shaft are rotating in a given direction and while said solenoid remains energized, said load being adapted to be released for lowering by gravity drop while 6 said motor and shaft are operating in a direction opposite to that for load raising, said motor, upon speed of load drop exceeding that of said motor and shaft while said torque release remains effective as a drive, being adapted to reduce in current value to release said solenoid and render said torque release ineffective as a drive, braking means carried by said torque release carrier centrifugally responsive to the rotation of said carrier at a speed in excess of that of said motor to brake said load drop, said solenoid, upon the braking action of said carrier, being adapted to be reenergized to compress the plates of said torque release to reenergize said solenoid and reestablish said torque release in driving engagement between said gear train and output shaft. 2. An actuator for raising and lowering a load of the drop type comprising a reversible electric motor and shaft and a gear train driven thereby, an actuator output shaft in driving engagement with said load, a multiple friction plate torque release in engagement with said gear train,

a torque release carrier which also carries an over-riding clutch in engagement with said output shaft, a solenoid and a solenoid rod operated by said solenoid to be retracted when said solenoid is energized for compressing the plates of said torque release for rendering said torque release an effective drive between said gear train and said clutch to drive said output shaft to raise said load and means for lowering said load by gravity and regulating its speed of drop, said last named means comprising braking means, carried by said rotating torque release carrier, said breaking means including centrifugally responsive members that are centrifugally responsive to a speed greater than that of the reverse rotation of said motor and shaft for load lowering purposes while said over-riding clutch remains ineffective and upon deenergization of said solenoid in response to said excess speed load drop, for braking the rotation of said carrier, said solenoid upon the braking action on said carrier by said brake, being adapted to be reenergized to retract said solenoid rod to compress the plates of said torque release to reestablish said torque release as a driving means between said gear train and said output shaft.

3. An actuator for raising and lowering a load of the drop type comprising a reversible electric motor and shaft and a gear train driven thereby, an actuator output shaft in driving engagement with said load, a multiple friction plate torque release in engagement with said gear train, a torque release carrier which also carries an over-riding clutch in engagement with said output shaft, a solenoid and a solenoid rod operated by said solenoid to be retracted when said solenoid is energized for compressing the plates of said torque release for rendering said torque release an effective drive between said gear train and said clutch to drive said! output shaft to raise said load and means for lowering said load by gravity and regulating its speed of drop, said last named means comprising braking means, carried by said rotating torque release carrier and centrifugally responsive to a speed greater than that of the reverse rotation of said motor and shaft for load lowering purposes while said over-riding clutch remains ineffective and upon deenergization of said solenoid in response to said excess speed load drop, for braking the rotation of said carrier, said solenoid upon the braking action on said carrier by said brake, being adapted to be reenergized to amassed.

retract :said solenoid; .rod .to' compress the .plates of.;.said:torque release to; reestablish said torque releasevasra driving; means; between said gear trainand said output shaftsaidbraking means comprising a pair of opposed concave shoes with agseries ofballs therebetween carried by said carrieraanddrumsadjacent the outer faces of said shoes and carried .by the stationary housing for said :actuator.

4-; An: actuator for raising and lowering a load oi-the drop type comprising a reversible electric motorandshaft and a gear train driven thereby, actuator output shaft in driving engagement withsaid load, a multiple friction plate torque release. in engagement with said gear train, a torque release carrier which also carries an overridingclutch in engagement wit-h said output shaft; a solenoid and a solenoid rod operated by saidgsolenoid to be retracted when said solenoid is.:energized for compressing the plates of said torque release for rendering said torque-release aneifective drive between said gear train-and said clutch to drive said output shaft to raise said load and means for lowering said lead by gravity and regulating its speed of drop, said last named mean comprising braking means, carried by said rotatingtorque release carrier and centrifugally, responsive to a-speed greater than that-of the reverse rotation. of said motor and shaft for loadlowering purposes while said overriding clutch remains ineffective and upon deenergization of said solenoid in response to said excess speed: load drop, for braking the rotationof said carrier, said solenoid upon the braking: -action :on' said carrier by; said..-brake, being; adapted to be reenergized to retract-said. sole-- noid rod to compress -the;-platesof1said torque release to reestablishsaid. torque release as a driving means between said gear train andsaid.

output'shaft; said braking means comprising a pair'of opposedconcave shoes with a series of' REFERENCES 'CITED' The followingreferences are of record. in the file of this patent:

UNITED STATES PATENTS Number Name 1 Date 1,916,173 Lansing ,June 2'7, 1933 3,927,714 Nardone Sept. 19, 1933- 19395105 Nardone Dec. 12, 1933 2,429,425 Nardone. .Oct.- .21, 1947. 2,451,169 Nardone Oct. 12,-1948 2,479,019 Ochtman Augflfi, 1949 2,480,212 Baines" Aug. 30, 1949 

